As a documentclass I use
book. Chapters always start on the right hand side.
How can I turn it off? I don't want to have empty pages. I don't care on which side starts new chapter.
Use the document class option
There are two related document class options:
Also the margins are differently treated in
The default behavior can be changed by specifying such an option when loading the class, for example
Besides the standard classes, further classes support these options, such as